Attention should be paid to the use of chemical weeding in corn fields?

Attention should be paid to the use of chemical weeding in corn fields? Please guide the use of chemical weeding in corn fields to pay attention to the following problems: 1. Improper selection of varieties different herbicide varieties have different control effects on weeds. Some farmers do not know about chemical herbicides and mishear some random herbicides, thinking that as long as they are herbicides, they can kill weeds. As a result, the phenomenon of death and survival of seedlings in corn fields occurs from time to time. At present, most of the herbicides used in corn fields use plants to selectively control weeds. If the kinds of weeds in the field are different, the effect of the same chemical control is certainly different. Farmers hate the grass and blindly increase the dosage, which leads to the occurrence of drug damage to corn. For example, 50% Acetochlor EC is a widely used herbicide, which is also safe for corn. Before weeds are unearthed, Acetochlor has a good effect on Gramineae weeds such as Magnolia mandshurica and barnyardgrass, but has poor control effect on weeds such as amaranth, amaranth and hemp. 2. Improper use period (1) result in poor efficacy. The sensitivity of weeds to herbicides is different in different growth stages. Most Gramineae weeds and broad-leaved weeds are generally sensitive to herbicides in germination stage. Considering the safety of corn, most chemical herbicides in corn field are soil treatment agents. When weeds are not unearthed before corn seedling and before corn three-leaf stage and before two-leaf stage of weeds after sowing, they have ideal control effect on weeds and are safe to corn seedlings. If it is used after the five-leaf stage of corn and the four-leaf stage of weeds, not only the control effect on weeds is poor, but also the corn will be damaged by drugs. For example, 40% Acetochlor atrazine (Acetochlor atrazine) is a common herbicide in corn field in the past few years. If it is used according to technical rules, the herbicide spectrum is broad, and the efficacy is ideal, but some farmers do not see weeds and do not apply herbicides. When the grass is large, the effect is still not good. (2) causing serious drug damage. The same herbicide, especially soil treatment agent, should be used in front of maize seedlings. The younger the corn seedling is, the stronger the resistance to herbicides is. For example, 40% SE is a relatively safe herbicide in the current market. When it is used in soil treatment from pre-seedling to post-seedling 3-leaf stage, it is not only safe for corn, but also has strong seedlings and black and thick leaves, but if it is used after 5-7 leaf stage, it is safe for corn. It often leads to yellow spot to yellow blight of maize leaves and inhibits the growth. (3) resulting in a lot of corn herbicides remaining in the following crop, the residual period is long, such as 38% atrazine SC, the residual period in the soil is more than 3 months, if the drug is too late and the dosage is too large, it will directly affect the following crops (wheat, etc.). 3. Improper application of herbicides the application method of herbicides is complicated, strict technical requirements and a little negligence, which not only affect the effect of weeding, but also often cause crop drug damage. For example, when some farmers use 20% paraquat AS, 41% Rongda AS and other herbicides in corn fields, they inadvertently protect corn, and the grass and seedlings die together, and some use soil treatment agents as stem and leaf treatments. The drug damage of corn is often serious, but it has no effect on weeds. On the contrary, when the stem and leaf treatment agent was used in soil treatment, it had no effect. 4. Improper dosage (1) do not understand the normal dosage of each herbicide in the corn field has its correct dosage under certain conditions, mainly through experiments and applications, such as 40% SE, in the light loam corn field non-early days, 180 mu 220 ml per mu, the weeding effect is ideal, when less than 180ml, the effect is often very poor, while higher than 250ml, drug damage often occurs. In the current corn fields with high stubble of wheat, the use of herbicides in wheat intercropping corn after wheat harvest should generally increase the amount of herbicides by 10% to 20%. (2) the adsorption capacity of sandy land to herbicide is poor, and it is easy to leach with water, and the adsorption capacity of clayey soil to herbicide is strong. The amount of soil treatment agent should be increased in the order of sand, loam and clay, soil organic matter can adsorb and decompose herbicides, and the land with high organic matter content should appropriately increase the amount of herbicides. 5. Uneven spraying and insufficient water use. Any pesticide spraying needs to be atomized well. Only when it is even and considerate can it have a good effect. When chemical weeding in corn field is carried out with soil treatment agent, only when the fog drop is fine, the amount of water is sufficient and sprayed evenly, the drug film can be formed on the soil surface and has the effect of inhibiting the emergence of weed buds. Spray uneven, weeds sprouts unearthed without the film will have no effect. The water consumption is insufficient, and most of the medicine liquid falls on the wheat stubble, which does not have the desired effect. 6. Droplet drift is serious due to the current household management of land, small plots and different crops, which belongs to a typical small and full flower arrangement planting mode. In the process of spraying, careless operation often causes drug damage to sensitive crops in adjacent plots, such as cotton, melons, vegetables and so on. In particular, the use of motorized fogging machine to spray corn herbicide, the drift phenomenon is more serious, such as windy weather, often cause serious drug damage to sensitive crops downwind. 7. Cause the change of weed species in corn field most of the herbicides in corn field are selective, and the resistance of all kinds of weeds to certain herbicides is different. if a herbicide is used for a long time, some weeds will be controlled, while other weeds will become the dominant species, which will change the species of weeds in the corn field, thus increasing the difficulty of chemical weeding. Second, countermeasure 1. Strengthen the training and guidance of chemical weeding techniques; the agricultural sector should strengthen the training and guidance to pesticide operators and users so that they can know more about chemical weeding and avoid various risks. 2. The correct selection of chemical herbicides can be divided into killing herbicides and selective herbicides, and selective herbicides can be divided into soil treatment agents and stem and leaf treatment agents, and can be divided into contact type and transport type. Herbicides with different ingredients and varieties have different herbicide spectrum, adaptability and sensitivity to crops. Before use, we should fully understand the performance of all kinds of herbicides, and grasp their applicable dosage, applicable period, appropriate methods, matters needing attention, etc., and correctly select herbicide varieties according to soil quality, climate, maize growth period, weed species, grass size and other factors. 3. During the suitable period of application, soil treatment agents should be applied to the soil before the 2-leaf stage of weeds before maize sowing and before the 3-leaf stage of corn, and make full use of the period when the weeds are resistant to herbicides and the buds of weeds are most sensitive to herbicides. On the other hand, the stem and leaf treatment agent should implement protective spray after the 5-leaf stage of corn and avoid the corn plant as far as possible in order to achieve the best effect. 4. To select the appropriate dosage is to determine the dosage of this variety in a certain growth period of local corn according to the guidance of agricultural technicians and pesticide instructions. Second, when using soil treatment agent, the dosage of sandy soil is lower than that of clayey soil, and when the content of organic matter is more than 3%, it should be increased appropriately. 5. To master the method of weeding in corn field, soil treatment agent can be selected to spray on the ground before seedling after sowing. After the 5-leaf stage of corn, the stem and leaf treatment agent should be sprayed directly on the stems and leaves of weeds, and attention must be paid to the use of inter-row directional spraying technology, a protective cover should be placed at the sprayer head, and the spray head should be sprayed on the grass along the ridge, so as not to splash the liquid on the corn plant as far as possible. Spray corn herbicide to use enough water, generally more than 40-50 kg per mu, spray must be safe and thoughtful, do not re-spray, do not leak spray, do not increase the dosage at will, spray with manual sprayers such as Gong Nong-16, generally do not encourage the use of motorized sprayers. 6. pay attention to the weather conditions, most of the chemical herbicides in the corn field are soil treatment agents, and should be sprayed on overcast and rainy days or after watering, that is, when the soil is wet, which is beneficial to the formation of drug film and improve the control effect. In order to avoid drug damage to crops other than cornfields, use medicine in windless weather and keep the sprinkler down to prevent fog droplets from drifting over a long distance. In a word, chemical weeding in corn field has been popularized, but there are many technical problems. In order to improve and apply this technology continuously, it is necessary to improve the drug use technology of farmers as soon as possible in order to achieve the desired results. Click to get more corn planting techniques click to get more herbicide application techniques click to get more pesticide application techniques